Chapter 16 - Enhanced Oil Recovery

Abstract

Enhanced oil-recovery methods are becoming popular with respect to the limited worldwide resources of crude oil. The estimated worldwide production from enhanced oil-recovery projects and heavy-oil projects at the beginning of 1996 was approximately 2.2 million barrels per day (bpd). . Enhanced oil-recovery processes include chemical and gas floods, steam, combustion, and electric heating. Gas floods, including immiscible and miscible processes, are usually defined by injected fluids (carbon dioxide, flue gas, nitrogen, or hydrocarbon). Steam projects involve cyclic steam (huff and puff) or steam drive. Combustion technologies can be subdivided into those that auto-ignite and those that require a heat source at injectors. The other topics discussed are Chemical floods, which are identified by the chemical type that is injected. The most common processes are polymers, surfactants, and alkalis, but chemicals are often combined. The design of chemical injection-enhanced oil recovery projects can be more complicated than that of waterflood projects, whereas down-hole conditions are more severe than are those for primary or secondary recovery production of oil. Well injectivity is complicated by chemicals present in injected waters. Therefore, in addition to precautions used in waterfloods, chemical interactions, reduced injectivity, deleterious mixtures at producers, potential for accelerated corrosion, and possible well stimulations to counter reduced injectivity must be considered.